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            <h1 style="display: none">Edu_CodeForces#83 Div. 2</h1>
            
              <p class="note note-info">
                
                  本文最后更新于：2 年前
                
              </p>
            
            <div class="markdown-body" id="post-body">
              <p><del>放弃了靠自己的英语水平理解题目，这次做题达到了我的最速，然而还是掉分了……</del></p>
<p><strong>传送门</strong>：<a target="_blank" rel="noopener" href="https://codeforces.com/contest/1312">【Educational Codeforces Round 83 (Rated for Div. 2)】</a></p>
<a id="more"></a>
<hr>
<h4 id="A-Two-Regular-Polygons"><a href="#A-Two-Regular-Polygons" class="headerlink" title="A. Two Regular Polygons"></a>A. Two Regular Polygons</h4><p>刚打开题面发现是几何题差点没把我吓死(</p>
<p>看了看题目发现其实还好，犹豫了一下是不是正解，于是花了3分钟才完成这题。</p>
<p>我能选的无非就原来这么些顶点，只要能够平均分配就一定有方案，如果不能平均分配就没有方案，所以 <strong>%%%</strong> 就完事</p>
<div class="hljs"><pre><code class="hljs cpp"><span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;iostream&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstring&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdio&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;algorithm&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cmath&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;map&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;set&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;queue&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdlib&gt;//rand()</span></span>
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ll;
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">unsigned</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ull;
<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">string</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cin</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cout</span>;

<span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">main</span><span class="hljs-params">()</span></span>&#123;
    <span class="hljs-built_in">std</span>::ios::sync_with_stdio(<span class="hljs-number">0</span>);<span class="hljs-built_in">cin</span>.tie(<span class="hljs-number">0</span>);<span class="hljs-built_in">cout</span>.tie(<span class="hljs-number">0</span>);
    <span class="hljs-comment">//freopen(&quot;in.in&quot;, &quot;r&quot;, stdin);</span>
    <span class="hljs-keyword">int</span> T,x,y;
    <span class="hljs-built_in">cin</span> &gt;&gt; T;
    <span class="hljs-keyword">while</span>(T--)&#123;
        <span class="hljs-built_in">cin</span> &gt;&gt; x &gt;&gt; y;
        <span class="hljs-keyword">if</span>(x % y == <span class="hljs-number">0</span>) <span class="hljs-built_in">cout</span> &lt;&lt; <span class="hljs-string">&quot;YES\n&quot;</span>;
        <span class="hljs-keyword">else</span> <span class="hljs-built_in">cout</span> &lt;&lt; <span class="hljs-string">&quot;NO\n&quot;</span>;
    &#125;
    <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
&#125;</code></pre></div>
<hr>
<h4 id="B-Bogosort"><a href="#B-Bogosort" class="headerlink" title="B. Bogosort"></a>B. Bogosort</h4><p>没看到标题，看到题目描述人傻了，这怎么做，看看时间<code>2s</code>，难道要暴力？然后人傻了，难道我<strong>T2</strong>就不会做了……突然想起似乎前面几场比赛都有一题<code>sort</code>一下就完事，突然发现这题也可以，于是开开心心的在10分钟写完了这题。</p>
<p>观察得到这样一个性质，对于$a_i$和$a_j$当存在$i<j$时，根据不等式规律：当$a<b$ 且 $c>d$，必定存在 $a-c &lt; b-d$，此题中$a$，$b$就是$i$，$j$，所以只要保证 $a_i&gt;a_j$ 就必定满足条件。</p>
<div class="hljs"><pre><code class="hljs cpp"><span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;iostream&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstring&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdio&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;algorithm&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cmath&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;map&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;set&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;queue&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdlib&gt;//rand()</span></span>
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ll;
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">unsigned</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ull;
<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">string</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cin</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cout</span>;
<span class="hljs-function"><span class="hljs-keyword">inline</span> <span class="hljs-keyword">bool</span> <span class="hljs-title">cmp</span><span class="hljs-params">(<span class="hljs-keyword">int</span> x,<span class="hljs-keyword">int</span> y)</span></span>&#123;<span class="hljs-keyword">return</span> x &gt; y;&#125;
<span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">main</span><span class="hljs-params">()</span></span>&#123;
    <span class="hljs-comment">//std::ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);</span>
    <span class="hljs-comment">//freopen(&quot;in.in&quot;, &quot;r&quot;, stdin);</span>
    <span class="hljs-keyword">int</span> T;
    <span class="hljs-built_in">cin</span> &gt;&gt; T;
    <span class="hljs-keyword">while</span>(T--)&#123;
        <span class="hljs-keyword">int</span> n , a[<span class="hljs-number">111</span>];
        <span class="hljs-built_in">cin</span> &gt;&gt; n;
        <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> i = <span class="hljs-number">1</span>;i &lt;= n;++i) <span class="hljs-built_in">cin</span> &gt;&gt; a[i];
        <span class="hljs-built_in">std</span>::sort(a+<span class="hljs-number">1</span>,a+n+<span class="hljs-number">1</span>,cmp);
        <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> i = <span class="hljs-number">1</span>;i &lt;= n;++i) <span class="hljs-built_in">cout</span> &lt;&lt; a[i] &lt;&lt; <span class="hljs-string">&quot; &quot;</span>;
        <span class="hljs-built_in">cout</span> &lt;&lt; <span class="hljs-string">&quot;\n&quot;</span>;
    &#125;
    <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
&#125;</code></pre></div>
<hr>
<h4 id="C-Adding-Powers"><a href="#C-Adding-Powers" class="headerlink" title="C. Adding Powers"></a>C. Adding Powers</h4><p>最初的设想是进行一波预处理，把所有<code>0</code>过滤掉方便处理，然后不断进行如下操作</p>
<p>1.遍历数组<code>a[]</code></p>
<ul>
<li>如果存在 $\forall i\in[1,n]\bigcap N_+,a_i\equiv0 \mod{k}$，则直接进行<code>2.</code></li>
<li>如果只有一个元素$a_p$不满足上述条件，则将该元素剔除后进行<code>2.</code></li>
<li>如果不止一个元素不满足上述条件，则答案为<code>NO</code></li>
</ul>
<p>2.$a_i=\frac{a_i}{k}$</p>
<p>3.返回<code>1.</code></p>
<p>然而<code>WA4</code>，康了半天也没康出该所以然，所以开始想别的办法。</p>
<p>想到进制转换，虽然第一次没过，但是重构了一下还是过了。</p>
<p>将输入的元素转化为$k$进制数，根据题意有该$k$进制数只能为<code>01</code>串，即每一位最多为<code>1</code>，即代表$p^k$最多使用一次。同样的，对于不同元素的同一位也最多只能有一个$1$。可以简化如下：</p>
<div class="hljs"><pre><code class="hljs cpp"><span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;iostream&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstring&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdio&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;algorithm&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cmath&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;map&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;set&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;queue&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdlib&gt;//rand()</span></span>
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ll;
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">unsigned</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ull;
<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">string</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cin</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cout</span>;
<span class="hljs-keyword">int</span> n,k,maxx;
ll a[<span class="hljs-number">10000</span>],x;
<span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">main</span><span class="hljs-params">()</span></span>&#123;
    <span class="hljs-built_in">std</span>::ios::sync_with_stdio(<span class="hljs-number">0</span>);<span class="hljs-built_in">cin</span>.tie(<span class="hljs-number">0</span>);<span class="hljs-built_in">cout</span>.tie(<span class="hljs-number">0</span>);
    <span class="hljs-comment">//freopen(&quot;in.in&quot;, &quot;r&quot;, stdin);</span>
    <span class="hljs-keyword">int</span> T;
    <span class="hljs-built_in">cin</span> &gt;&gt; T;
    <span class="hljs-keyword">while</span>(T--)&#123;
        <span class="hljs-keyword">bool</span> flag = <span class="hljs-literal">false</span>;
        <span class="hljs-built_in">cin</span> &gt;&gt; n &gt;&gt; k;
        <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> i = <span class="hljs-number">1</span>;i &lt;= n;++i)&#123;
            <span class="hljs-built_in">cin</span> &gt;&gt; x;
            <span class="hljs-keyword">int</span> p = <span class="hljs-number">0</span>;
            <span class="hljs-keyword">while</span>(x)&#123;
                a[++p] += x % k , x /= k;
                <span class="hljs-keyword">if</span>(a[p] &gt; <span class="hljs-number">1</span>) flag = <span class="hljs-literal">true</span>;
            &#125;
        &#125;
        <span class="hljs-keyword">if</span>(flag) <span class="hljs-built_in">cout</span> &lt;&lt; <span class="hljs-string">&quot;NO\n&quot;</span>;
        <span class="hljs-keyword">else</span> <span class="hljs-built_in">cout</span> &lt;&lt; <span class="hljs-string">&quot;YES\n&quot;</span>;
        <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> i = <span class="hljs-number">1</span>;i &lt;= maxx;++i) a[i] = <span class="hljs-number">0</span>;
    &#125;
    <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
&#125;</code></pre></div>
<hr>
<h4 id="D-Count-the-Arrays"><a href="#D-Count-the-Arrays" class="headerlink" title="D. Count the Arrays"></a>D. Count the Arrays</h4><p>还没开始做就听大佬们在说<strong>卢卡斯定律卢卡斯定律</strong>，可我一开始压根不知道卢卡斯定律是什么东西(于是切完C马上且查，结果只是个取模组合数……所以说为什么我上次做取模组合数没查到卢卡斯(迫真，其实完全没必要卢卡斯，费马小定理求逆元即可。</p>
<p>//然后是公式的推导过程。</p>
<p>我们需要在$m$个数里选择$(n-1)$个<em>(有且仅有一个重复)</em>，即$C<em>m^{n-1}$，然后这些元素的最大值就作为峰值，也就是索引$i$对应的元素。剩下的$(n-2)$个元素中得选出一个作为重复元素，所以要乘上$C</em>{n-2}^1$。最后还剩下$(n-3)$个元素，每一个元素都有放峰值左边和右边两种状态，且各自不相干，所以还要乘上$2^{n-3}$。所以式子如下：</p>
<ul>
<li>$ans = (n-3)C_m^{n-1}*2^{n-3} \mod p$</li>
</ul>
<div class="hljs"><pre><code class="hljs cpp"><span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;iostream&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstring&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdio&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;algorithm&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cmath&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;map&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;set&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;queue&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdlib&gt;//rand()</span></span>
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ll;
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">unsigned</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ull;
<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">string</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cin</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cout</span>;
<span class="hljs-keyword">int</span> p = <span class="hljs-number">998244353</span>;
ll _power(<span class="hljs-keyword">int</span> x,<span class="hljs-keyword">int</span> P)&#123;
    <span class="hljs-keyword">if</span>(P &lt; <span class="hljs-number">0</span>) <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
    ll ans = <span class="hljs-number">1</span> , base = x;
    x %= p;
    <span class="hljs-keyword">while</span>(P)&#123;
        <span class="hljs-keyword">if</span>(P &amp; <span class="hljs-number">1</span>) ans = (ans * base) % p;
        base *= base , base %= p;
        P &gt;&gt;= <span class="hljs-number">1</span>;
    &#125;
    <span class="hljs-keyword">return</span> ans;
&#125;
<span class="hljs-function">ll <span class="hljs-title">C</span><span class="hljs-params">(ll n,ll m)</span></span>&#123;
    <span class="hljs-keyword">if</span>(n &lt; m) <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
    m = <span class="hljs-built_in">std</span>::min(m,n - m);
    ll up = <span class="hljs-number">1</span> , down = <span class="hljs-number">1</span>;
    <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> i = <span class="hljs-number">1</span>;i &lt;= m;++i)&#123;
        up *= n-i+<span class="hljs-number">1</span>, up %= p;
        down *= i , down %= p;
    &#125;
    <span class="hljs-keyword">return</span> up * _power(down,p<span class="hljs-number">-2</span>) % p;
&#125;
<span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">main</span><span class="hljs-params">()</span></span>&#123;
    <span class="hljs-built_in">std</span>::ios::sync_with_stdio(<span class="hljs-number">0</span>);<span class="hljs-built_in">cin</span>.tie(<span class="hljs-number">0</span>);<span class="hljs-built_in">cout</span>.tie(<span class="hljs-number">0</span>);
    <span class="hljs-comment">//freopen(&quot;in.in&quot;, &quot;r&quot;, stdin);</span>
    <span class="hljs-keyword">int</span> n , m;
    <span class="hljs-built_in">cin</span> &gt;&gt; n &gt;&gt; m;
    ll ans = <span class="hljs-number">0</span>;
    <span class="hljs-keyword">if</span>(n != <span class="hljs-number">2</span>) <span class="hljs-built_in">cout</span> &lt;&lt; (((n<span class="hljs-number">-2</span>) * C(m,n<span class="hljs-number">-1</span>) % p) * _power(<span class="hljs-number">2</span>,n<span class="hljs-number">-3</span>)) % p;
    <span class="hljs-keyword">else</span> <span class="hljs-built_in">cout</span> &lt;&lt; <span class="hljs-number">0</span>;
    <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
&#125;</code></pre></div>
<hr>
<h4 id="E-Array-Shrinking"><a href="#E-Array-Shrinking" class="headerlink" title="E. Array Shrinking"></a>E. Array Shrinking</h4><p>区间<code>dp</code>的味道扑面而来，然而我已经好久没有写过<code>dp</code>了(迫真</p>
<p><code>dp[i][j]</code>记录<code>a[i]~a[j]</code>的最短长度(若干次合并后)，同时用<code>num[i][j]</code>表示<code>a[i]~a[j]</code>合并后的数字。</p>
<p>存在如下转移：</p>
<ul>
<li><code>dp[i][j]</code> = $min$(<code>dp[i][j]</code>,<code>dp[i][k]</code>+<code>dp[k+1][j]</code>)</li>
<li>当存在<code>dp[i][k]</code>和<code>dp[k+1][j]</code>均为1，且<code>num[i][k]</code>和<code>num[k+1][j]</code>相同时，可以进行合并操作</li>
</ul>
<div class="hljs"><pre><code class="hljs cpp"><span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;iostream&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstring&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdio&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;algorithm&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cmath&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;map&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;set&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;queue&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span><span class="hljs-meta-string">&lt;cstdlib&gt;//rand()</span></span>
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ll;
<span class="hljs-keyword">typedef</span> <span class="hljs-keyword">unsigned</span> <span class="hljs-keyword">long</span> <span class="hljs-keyword">long</span> ull;
<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">string</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cin</span>;<span class="hljs-keyword">using</span> <span class="hljs-built_in">std</span>::<span class="hljs-built_in">cout</span>;
<span class="hljs-keyword">int</span> n,a[<span class="hljs-number">555</span>],dp[<span class="hljs-number">555</span>][<span class="hljs-number">555</span>],num[<span class="hljs-number">555</span>][<span class="hljs-number">555</span>];
<span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">main</span><span class="hljs-params">()</span></span>&#123;
    <span class="hljs-built_in">std</span>::ios::sync_with_stdio(<span class="hljs-number">0</span>);<span class="hljs-built_in">cin</span>.tie(<span class="hljs-number">0</span>);<span class="hljs-built_in">cout</span>.tie(<span class="hljs-number">0</span>);
    <span class="hljs-comment">//freopen(&quot;in.in&quot;, &quot;r&quot;, stdin);</span>
    <span class="hljs-built_in">cin</span> &gt;&gt; n;
    <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> i = <span class="hljs-number">1</span>;i &lt;= n;++i) <span class="hljs-built_in">cin</span> &gt;&gt; a[i];
    <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> i = <span class="hljs-number">1</span>;i &lt;= n;++i)&#123;
        <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> j = i;j &lt;= n;++j)&#123;
            <span class="hljs-keyword">if</span>(i == j) num[i][j] = a[i];
            dp[i][j] = j - i + <span class="hljs-number">1</span>;
        &#125;
    &#125;
    <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> len = <span class="hljs-number">2</span>;len &lt;= n;++len)&#123;
        <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> i = <span class="hljs-number">1</span>,j = len;j &lt;= n;++i,++j)&#123;
            <span class="hljs-keyword">for</span>(<span class="hljs-keyword">register</span> <span class="hljs-keyword">int</span> k = i;k &lt; j;++k)&#123;
                dp[i][j] = <span class="hljs-built_in">std</span>::min(dp[i][j],dp[i][k]+dp[k+<span class="hljs-number">1</span>][j]);
                <span class="hljs-keyword">if</span>(dp[i][k] == dp[k+<span class="hljs-number">1</span>][j] &amp;&amp; dp[i][k] == <span class="hljs-number">1</span> &amp;&amp; num[i][k] == num[k+<span class="hljs-number">1</span>][j])&#123;
                    dp[i][j] = <span class="hljs-number">1</span> , num[i][j] = num[i][k] + <span class="hljs-number">1</span>;
                &#125;
            &#125;
        &#125;
    &#125;
    <span class="hljs-built_in">cout</span> &lt;&lt; dp[<span class="hljs-number">1</span>][n] &lt;&lt; <span class="hljs-string">&quot;\n&quot;</span>;    
    <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
&#125;</code></pre></div>
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          $("body").append($i);
          //animate() 方法执行 CSS 属性集的自定义动画。
          //该方法通过CSS样式将元素从一个状态改变为另一个状态。CSS属性值是逐渐改变的，这样就可以创建动画效果。
          //详情请看http://www.w3school.com.cn/jquery/effect_animate.asp
          $i.animate({
            //将原来的位置向上移动180
            "top": y - 180,
            "opacity": 0
            //1500动画的速度
          }, 1500, function () {
            //时间到了自动删除
            $i.remove();
          });
        });
      })
      ;
    </script>
  














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